I Bought my S4 brand new in 2011 and ran lovely on my MacBook Pro late 2011 eventually upgraded to macOS High Sierra 10.13.6 ,However many years later my laptop died and sadly Now have to use my partner's Mac book pro - macOS Catalina 10.15.7
Here is the problem , I down loaded a demo of Traktor Pro 4 and it was working …so I bought the upgrade from Pro 2 using , Native access 3.16 loads the software but fails to run ?